<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			var a = +"123";
			document.write(typeof(a) + '<br>');
			alert(a + 1);

			var b = +"abc";
			document.write(typeof(b) + '<br>');
			alert(b);
			alert(b + 1);
		</script>
	</body>
</html>
